Baron St John of Basing is a former title in the Peerage of England. The family of St John of Basing in Hampshire and of Halnaker in Sussex was descended in the male line from the Norman Hugh de Port (d.1091) lord of the manor of Port-en-Bessin in Normandy who took part in the Norman Conquest of England in 1066, and was subsequently granted 53 manors in Hampshire. They had adopted the St. John surname by 1205.) The later Barons St John of Bletso (created 1582) in Bedfordshire is suggested to have been a cadet line of St John of Basing, but clear evidence is lacking.